The defence secretary, John Hutton, flew into Basra today for a service to honour the 179 British personnel killed during the six-year conflict in Iraq.

The UK's military presence in the country is coming to an end and Hutton arrived as the bulk of the 3,700 servicemen and women were carrying out their final duties before flying home.

The defence secretary will attend a ceremony at the memorial wall in front of the 20th Armoured Brigade headquarters on the main coalition military base in Basra where the names of the British, Italian, Dutch, Danish, American and Romanian troops and the civilian contractors killed since 2003, will be read out.

Meanwhile Iraq's prime minister, Nouri al-Maliki, is in London for talks with Gordon Brown and a business conference designed to encourage investment as Iraq emerges from six years of war and more than a decade of sanctions.

Maliki will meet cabinet ministers in 10 Downing Street before holding talks with Brown, after which the two leaders are due to hold a joint press conference.

High on the agenda is certain to be the process whereby responsibility for the southern city of Basra is being handed over to the US military ahead of its eventual return to full Iraqi control.

The security situation around Basra has improved in recent months thanks in part to a major Iraqi army-led operation against militias, known as Charge of the Knights, which began in March last year. All but about 400 of the remaining British troops in Iraq will be withdrawn by 31 July.

Maliki and the oil minister, Hussain al-Shahristani, will use the visit to try to cash in on the country's improved security situation when they meet representatives of about 250 companies – including Shell and Rolls-Royce – to discuss opportunities for trade and investment.

The one-day Iraq Invest conference, being held by the Iraqi government's national investment commission with the support of the UK Department for International Development, is the first such event to be held in London since the 1990s. It will be addressed by the business secretary, Lord Mandelson, and the international development secretary, Douglas Alexander.